1. Field of the Invention
This invention relates to surgical instruments and is directed more particularly to endoscopes by which surgical sites may be viewed by the operating physician.
2. Description of the Prior Art
Endoscopes, which are instruments used to inspect cavities or openings or selected sites, have found a number of applications in medicine and other technologies. In the field of medicine, the use of endoscopes permits inspection of organs or tissue for the purpose of facilitating the obtainment of biological specimens or the viewing of a surgical site for the purpose of facilitating the manipulation of other surgical instruments so as to avoid invasive and traumatizing surgical procedures.
Endoscopes generally comprise an insertion portion that is designed to be inserted into a patient. Older conventional endoscopes used in medicine contain an objective lens unit at the distal (forward) end of the insertion portion which transmits an image of the area forward of the objective lens unit to a remote eye-piece for viewing by the surgeon, the image being transmitted to the eye-piece via an image forwarding means in the form of a relay lens set, or an optical fiber bundle unit. In more recent years, in place of the eye-piece and at least part of the image forwarding means, it has been preferred to provide a small size solid state video imaging device, such as one constituting a CCD chip, in the imaging plane of the objective lens, and applying the output of that video imaging device via a suitable electronic transmission system to a video monitor for viewing by a user. The combination of an objective lens and a solid state video imaging device constitutes a video camera. With both types of image transmitting and viewing arrangements, a surgeon can view the displayed image and use the information conveyed by that image to manipulate the endoscope and also other surgical instruments that have been inserted into the patient via another incision or opening in the patient's body.
Video endoscopes also may be of the stereo variety, comprising optical means for generating first and second optical images, and video imaging means for generating first and second electrical signals in response to the first and second optical images respectively. The present state of the art of endoscopes prior to this invention is demonstrated by various U.S. and foreign patents ands also pending patent applications. By way of example, the present state of the art is demonstrated by the following U.S. patent applications: (1) Ser. No. 08/286543, filed Aug. 5, 1994 by K. Hori; (2) Ser. No. 08/319,886, filed Oct. 7, 1994 by K. Hori et al; (3) Ser. No. 08/475,364, filed Jun. 7, 1995 by K. Hori et al, and (4) Ser. No. 08/545297, filed Oct. 20, 1995 by K. Hori et al; Those patent applications show and describe optical, electronic and mechanical components of a contemporary endoscope. The teachings of those patent applications are incorporated herein by reference thereto.
The insertion portions of conventional endoscopes usually have a generally rigid tubular construction but in some endoscopes the invention portion comprises a flexible tubular construction. In many instances, such constructions are consistent with the desired use of the endoscope. However, in some instances, as in some by-pass heart surgery procedures, it would be helpful to the attending physician to be able to configure the insertion portion of the endoscope to a selected shape to facilitate proper positioning of the camera in the patient or in relation to the surgical incision, and to have that insertion portion retain that shape until changed by the physician. For example, in certain heart surgery procedures, incisions commonly are made between the fourth and fifth ribs. The fourth and fifth ribs are separated vertically and one of the ribs is displaced forwardly to provide a vertical opening for insertion of the endoscope, and related surgical instruments, between the rib cage and the heart. The endoscope usually is inserted from below and moved upwardly. Because there is little room between the rib cage and the heart, there is considerable difficulty in properly positioning an endoscope at the surgical site. It would be helpful to the physician to be able to configure the insertion portion of the endoscope in a manner advantageous for entry and positioning relative to the surgical site, and have the endoscope maintain that configuration until changed by the physician. It also would be of value to the surgeon to be able to position and use the video camera in different situations without being restricted by the physical construction of the insertion portion. A further consideration of this invention is that prior endoscopes have been designed for particular procedures and are not suitable for use in other procedures.